define count 
proc( alist )
    l := alist;
    n := 0;
    while ! nullp(l) do
        l := cdr(l);
        n := n + 1
    od;
    return := n
end;
x:=5;
y:=10;
z:=15;
alist := [x,[y*10,100],[z*10,[1,2,3]]];
n := count( alist )
